The present invention relates generally to a method and systems for automatically controlling the intermittent flow of water, and more specifically to the automatic control of flow with respect to irrigation systems.
In the field of crop irrigation, there is a natural need for automated software tools and applications that may assist an owner in site operation, proper irrigation of a site for proper delivery of nutrients or pesticides to plants, and accurate crop data collection. For example, it may be desirable to have access to an automated interactive system which could be used to optimize or update an irrigation schedule in real time based on data collected from a crop, metrological conditions, soil conditions, and type of crops being irrigated. Such an automated interactive system can prevent plants from entering into a stressed state by adjusting irrigation in response to plant physiological conditions.
Irrigation systems supply water to soil. They are primarily used to assist in the growing of agricultural crops and maintenance of landscapes. Irrigation systems typically include valves, controllers, pipes, and emitters such as sprinklers or drip tapes. Irrigation systems are usually divided into zones based on the spatial resolution of the detection system, and irrigation is performed on that zone based on reflection from all the crop plants within that zone. Each zone may have a solenoid valve controlled via irrigation controller opening or closing irrigation zones. The irrigation controller may be a mechanical or electrical device signaling a zone to turn start irrigating a section of crop for a specific amount of time, or until it is turned off manually. It is desired that the number of control points in the system be individually addressable, however, all points that perform the same command may be connected in order to reduce communication over the power/signaling channels and optimize the cost of the technology.
Branch pipes in each zone are fed by a main line or common supply pipe. In existing systems, controllers are typically wired to the solenoid valves and the energy/power to actuate them is provided through a hardwired connection. Water can be pumped into the main line from a well source or a city supply.
More advanced irrigation systems may use smart controllers. A “smart controller” is typically a controller that is capable of adjusting the watering time by itself in response to current environmental conditions. Smart controllers determine current conditions using real time sensor data, historic and predicted weather data for the local area, soil moisture sensors (water potential or water content), size of the canopy, and greenness of the leaves, weather stations, or a combination of these.
Weather based smart controllers may provide a one dimensional answer to issues faced by irrigation sites. Although they may adjust the irrigation schedule for weather changes, and irrigate based on the needs of the field and, or landscape, they cannot account for other variables in the field, such as crop health or growth cycles. A smart controller may automatically reduce the watering times or frequency as the weather gets cooler determining that less water is needed, it does not take into account the individual need of the plants.
Systems utilizing individual plant health in a field under cultivation are known. For example, U.S. Pat. No. 5,220,876 discloses a variable rate fertilizer spreading apparatus that uses a soil map, (which may be acquired, for example, from an aerial infrared photograph), in order to determine the amount of fertilizer that is to be applied at each location within the field. For this purpose, a map is prepared (referred to as a “fertilizer map”), which shows a spatially distributed desired fertilizer level throughout the field, as well as a “status” map which shows corresponding existing fertilizer distribution throughout the field. The desired distribution of fertilizer as recorded in the “fertilizer map” is prepared in advance, based on determined physical characteristics of the field itself, including field topography, soil type, drainage, sun exposure, and the like. In order to provide for application of the proper amount of fertilizer to achieve the desired distribution, an “Expert System” utilizes artificial intelligence to perform the necessary calculations, based on the fertilizer map, the status map, the soil type and the types of chemicals that are being applied.
In a prescription forming control system disclosed in U.S. Pat. No. 5,919,242, a navigation controller controls the delivery rate of agricultural products by an applicator vehicle, as a function of the global position of the vehicle, based on digital maps which divide a field into “zones”, according for example to soil types. Several different products are delivered at differing rates depending on the soil content and the types of crops that are being cultivated. Similarly, U.S. Pat. No. 5,913,915 also discloses a multi-variable dispensing rate applicator for agricultural products in which a computerized control system stores a digital soil map containing information concerning the location of types of soils, topographic features, nutrient levels, soil compaction, drainage and the like. A map coordinate system allows for variable input control from side to side relative to the movement of the applicator system.
U.S. Pat. No. 6,199,000 B1 provides a precision farming method in which seeding, cultivating and/or harvesting operations are controlled using GPS technology in conjunction with a digital map of an agricultural field, which may be created using satellite, aircraft or other overhead imagery. High resolution photographs acquired in this manner are used to generate the digital map. According to this disclosure, relevant information can then be stored in the map (location of irrigation systems, previous planting locations of other crops and the like), and used to determine, for example, the location at which new crops/seeds should be planted.
Similar systems, in which soil characteristic maps are used to control automated agricultural machines are disclosed in U.S. Pat. Nos. 6,236,907 B1; 6,336,066 B1 and 6,141,614.
Each of the above prior art systems is based on the premise that the likely development of a crop planted in a particular field can be calculated based on physical soil and field conditions, such as the type of soil, topography, drainage, existing nutrient levels, compaction, etc. Accordingly, such information concerning soil and field conditions is stored in the form of a map or maps, which are then used to determine an optimum distribution of fertilizer or the like, based on complex, in some cases proprietary, algorithms. (See, for example, U.S. Pat. No. 5,220,876 at Column 8, lines 58 et seq.)
Such systems share the common deficiency that maps may have inherent variability from the moment was are created and may rely on GPS localization that is accurate at the level on the order of tens of feet. If the variable dispensing system needs to rely on a similar GPS localization system, the accuracy of the water/nutrients may be impaired as water/nutrients may be delivered to the wrong location, due to errors introduced by the GPS systems. The variable rate system is assuming that a mobile platform will move through the field and adjust the delivery of water/nutrients based on the map. One shortcoming of the above mentioned techniques is the two dimensional imaging of the top of the canopy yielding little information about the three dimensional shape and size of the plants. For example, satellite observation of the canopy having a spatial resolution of 30 meters by 30 meters will have reflection data from multiple plants/crops, making individual plant management impractical to implement. For single plant management it is desirable to have local sensor that can assess the condition of independent plants and be able to control the nutrients are delivered to individual plants. Without an accurate estimation of the biomass (volume of plant), for example, the estimation based on top imagery, the wrong amount of nutrients may be delivered. Variability may also reflect only the soil and other physical field characteristics, and in some instances the type of crop being cultivated. While these may be reasonable prognosticators of likely crop development, they do not and cannot take into account or adjust for actual crop growth due, for example, to the effects of weather, diseases, insects and the like. Nor can they take into account the effects of weather on the materials themselves after they have been applied—such as for example due to heavy rains and attendant runoff. They are also generally incapable of generating time variable dynamic crop prescriptions based on actual crop development throughout the growing season. Delivery of nutrients, multiple times per day, using a mobile platform may not be feasible due to time constrains in the operational efficiency.
Accordingly, it is an object of the present invention to provide a method and apparatus for controlling a spatially variable rate delivery apparatus for applying irrigation, fertilizer, and/or pesticides delivery through an irrigation infrastructure that may grow crops in a cultivated field which dynamically takes into account actual crop development throughout the growing season.
Another object of the invention is to provide such a method and apparatus for controlling application rates for agricultural irrigation, which automatically takes into account the effects of weather, disease and insects on crop development. Control system may need to optimize the delivery of instructions across the communications channels to increase time efficiency.
Another object of the invention is to provide a method and apparatus for the efficient delivery of variable rate scheduling across a large area, for example a farm, where multiple communication paths may be needed. The communication paths may be combined and may transfer information via wireless and wired pathways. Wireless and wired pathways may be combined to acquire sensor data and deliver the sensor data to a central computer that will communicate the data to control nodes. The information may be distributed from a central computer to a gateway based on the timeframe determined by an irrigation schedule that is delivered. The use of gateways may allow a partial or complete shut down of the system in case of a malfunction. Real time sensor data from the field may be integrated at the central computer such that the central computer will determine the required resource (water, fertilizer, and/or pesticide), optimize the delivery, and create priority list based on the availability of the resources.